@article {Mel{\'e}ndez2013243,
	title = {{Origin of water layer multiple phases with anomalously high amplitude in near-seafloor wide-angle seismic recordings}},
	journal = {Geophysical Journal International},
	volume = {196},
	number = {1},
	year = {2013},
	pages = {243{\textendash}252},
	abstract = {Water layer multiple seismic phases are recorded at ocean bottom seismometers and hydrophones as arrivals that correspond to the reflection of the primary phases at the sea-free air interface. In regions of low to moderate seabed relief, the shape of these phases mimics that of the primary phases with a traveltime delay that depends on the water layer thickness at the receiver location. Given their longer travel paths, multiple phases should have smaller amplitudes than their corresponding primary phases. However, depending on the geological context it can be relatively common to observe the opposite, which results in the identification of the multiple phases at longer offsets than the primary events. In this paper, we examine the origin of this apparently paradoxical phenomenon by analysing the combined effect of the major factors potentially involved: the source frequency content, the subsurface velocity distribution, the receiver-seafloor distance, the geometrical spreading and attenuation of sound waves and the ambient noise level.We use synthetic modelling to show that for certain combinations of these factors, the interference between the multiple and its reflection at the seafloor is constructive and has a higher amplitude than the primary wave. Our analysis indicates that in the most favourable cases the phases resulting from this interference can be observed at offsets some tens of kilometres longer than their corresponding primary phases, and thus they can provide useful information for velocity modelling. {\textcopyright} The Authors 2013. Published by Oxford University Press on behalf of The Royal Astronomical Society.},
	keywords = {ambient noise, Controlled source seismology, Controlled-source seismologies, Earthquake effects, Geometrical spread, hydrophone, Numerical approximations and analysis, numerical method, ocea, Seismology, Site effects, Wave propagation},
	issn = {0956540X},
	doi = {10.1093/gji/ggt391},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-84890885715\&partnerID=tZOtx3y1 http://www.scopus.com/inward/record.url?eid=2-s2.0-84890885715\&partnerID=40\&md5=a3729b5c20fafb9373a2a82c94b34990},
	author = {Mel{\'e}ndez, A.a and Sallar{\`e}s, V.a and Ranero, C.R.b R. and Kormann, J.c and Mel{\'e}ndez, A. and Sallar{\`e}s, V.}
}
@conference {Shariat-Panahi2008a,
	title = {{Ocean Bottom Seismometer (OBS): An instrument for marine seismic data acquisition}},
	booktitle = {2008 IEEE International Symposium on Industrial Electronics},
	year = {2008},
	month = {jun},
	pages = {1183{\textendash}1186},
	publisher = {IEEE},
	organization = {IEEE},
	abstract = {The OBS (Ocean Bottom Seismoemter) has been a key instrument for geophysical study of sea sub-bottom layers in the last decades. Now scientists are demanding highly relaible autonomous equipment capable of staying underwater for long periods of time and therefore handling large data storage. Power consumption of the acquisition system as well as a stable time base with temperature are the main issues in order to achieve high autonomy together with a good data quality. This paper presents a new Ocean Bottom Seismometer designed to be used in marine mid-term surveys. To achieve our goals, a new low power datalogger with high resolution and Signal-to-Noise Ratio (SNR) based on Compactflash memory card is designed to enable continous data acquisition. The equipment has been evaluated in real environmental conditions during a test cruise in 2006. {\textcopyright} 2008 IEEE.},
	keywords = {Acquisition system, Analog to digital converter, Geophone, Ocean bottom seismometer (OBS)},
	isbn = {978-1-4244-1665-3},
	doi = {10.1109/ISIE.2008.4677225},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-57849111983\&partnerID=tZOtx3y1},
	author = {Shariat-Panahi, S. and M{\`a}nuel, A. and Bermudez, A. and Ambros, M. and Sallar{\`e}s, V. and Molino, E.}
}
